The present invention relates generally to structures for electronic keyboard instruments. More particularly, the present invention relates to an improved structure for an electronic keyboard instrument which includes a lower case having a bottom plate for mounting thereon a keyboard unit on a portion thereof closer to a human player (i.e., on a player-side portion of the bottom plate) and an upper case having an upper plate to cover an upper portion of the lower case, and in which the upper case is overlapped on the lower case from above the lower case. Further, the present invention relates to an improved structure for an electronic keyboard instrument of a type where an operation section is provided on the upper surface of the upper plate.
In recent years, circuit boards to be incorporated in electronic keyboard instruments have been getting smaller and smaller, and it has become possible to house a circuit board in an upright position or posture within a housing. One example of such electronic keyboard instruments is disclosed in Japanese Patent Application Laid-open Publication No. 2004-171038. In the disclosed electronic keyboard instrument, an instrument housing comprises two major components: a housing body section; and a rear housing section.
The housing body section includes a bottom plate for mounting thereon a keyboard unit, and the bottom plate has openings in its upper and back sides. On the rear housing section, there are provided a roof plate portion (upper plate) that covers the upper opening of the housing body section and a back plate portion that covers the back opening of the housing body section. Further, a main circuit board is mounted, by screwing or the like, to the back plate portion of the rear housing section in an upright position. In assembling the housing of such a conventionally-known electronic keyboard instrument, the main circuit board is mounted to the back plate portion of the rear housing section, and then the rear housing section is mounted to the housing body section by being sled relative to the housing body section frontward, i.e. toward a position where a human player of the keyboard instrument is supposed to be at the time of playing (hereinafter also referred to as “player side”).
However, with the housing of the aforementioned conventionally-known electronic keyboard instrument, it is necessary to screw the main circuit board to the back plate portion of the rear housing section, and thus, separate screwing operation has to be performed. Consequently, there has been encountered the problem that the assembling work tends to be extremely cumbersome.
Further, an operation section, including operation buttons etc., is provided on the upper surface of the roof plate portion of the rear housing section. Wiring section, drawn out from the operation section, is wired beneath and along the lower surface of the roof plate portion and connected to the main circuit board. In some cases, the wiring is wired to pass across a neighborhood of the upper end surface of a heat radiating plate provided on the main circuit board beneath the roof plate. Consequently, heat is dissipated toward the wiring section, so that there would occur inconveniences, such as unwanted melting of the coating of the wiring due to the heat from the heat radiating plate. Further, Japanese Patent Application Laid-open Publication No. HEI-10-126015 discloses forming perforated lines in a printed circuit board and removing unnecessary circuit board portions along the perforated lines at the time of attachment or mounting of the circuit board. However, so far, the removed circuited board portions have been discarded as unnecessary.